U.S. patent number 5,486,273 [Application Number 07/781,141] was granted by the patent office on 1996-01-23 for resilient material and disposable, absorbent article comprising such a material.
This patent grant is currently assigned to Molnlycke AB. Invention is credited to Roy Hansson, Urban Widlund.
United States Patent |
5,486,273 |
Widlund , et al. |
January 23, 1996 |
Resilient material and disposable, absorbent article comprising
such a material
Abstract
A method for imparting varying degrees of elasticity in
different areas of a resilient material for disposable absorbent
articles includes providing an elastic material and removing
material from areas of the elastic material which are to be given a
lesser degree of resilience than remaining areas. At the same time
attached material parts are left in those areas of the elastic
material from which material has been removed.
Inventors: |
Widlund; Urban (Molnlycke,
SE), Hansson; Roy (Molndal, SE) |
Assignee: |
Molnlycke AB (Goteborg,
SE)
|
Family
ID: |
20376501 |
Appl.
No.: |
07/781,141 |
Filed: |
December 27, 1991 |
PCT
Filed: |
July 03, 1990 |
PCT No.: |
PCT/SE90/00475 |
371
Date: |
December 27, 1991 |
102(e)
Date: |
December 27, 1991 |
PCT
Pub. No.: |
WO91/00720 |
PCT
Pub. Date: |
January 24, 1991 |
Foreign Application Priority Data
Current U.S.
Class: |
264/154; 264/138;
428/131; 428/910; 604/358 |
Current CPC
Class: |
A61F
13/15707 (20130101); A61F 13/15731 (20130101); A61F
13/512 (20130101); A61F 13/51464 (20130101); A61F
13/51484 (20130101); A61F 13/513 (20130101); B26F
1/24 (20130101); A61F 13/15585 (20130101); A61F
2013/49088 (20130101); A61F 2013/51322 (20130101); A61F
2013/51429 (20130101); Y10S 428/91 (20130101); Y10T
428/24273 (20150115); A61F 2013/49042 (20130101) |
Current International
Class: |
A61F
13/15 (20060101); B26F 1/00 (20060101); B26F
1/24 (20060101); B28B 001/48 () |
Field of
Search: |
;428/131,132,137,138,192,284,913,910 ;264/138,153,154 ;604/358 |
References Cited
[Referenced By]
U.S. Patent Documents
|
|
|
4692163 |
September 1987 |
Widlund et al. |
|
Foreign Patent Documents
|
|
|
|
|
|
|
0098983 |
|
Jan 1984 |
|
EP |
|
0195113 |
|
Sep 1986 |
|
EP |
|
0302611 |
|
Feb 1989 |
|
EP |
|
0203820 |
|
Dec 1990 |
|
EP |
|
8406071-4 |
|
Jun 1987 |
|
SE |
|
1253664 |
|
Nov 1971 |
|
GB |
|
2218990 |
|
Nov 1989 |
|
GB |
|
Primary Examiner: Bell; James J.
Attorney, Agent or Firm: Burns, Doane, Swecker &
Mathis
Claims
I claim:
1. A method of imparting varying degrees of resilience to different
areas of an elastic material for absorbent, disposable articles,
comprising providing an elastic material, removing material from
areas of the elastic material which are to be given a lesser degree
of resilience than remaining areas of said elastic material while
also leaving attached material-parts in the areas of said elastic
material from which material has been removed in order to give
different areas of the elastic material different properties upon
being stretched.
2. A method according to claim 1, wherein said step of removing
material from said elastic material includes forming a pattern of
through-passing and/or blind holes in the plastic material.
3. A method according to claim 2, wherein blind holes are formed in
the elastic material and including removing material present
between said blind holes in a subsequent working stage to thereby
create larger areas from which material has been removed.
4. A thin elastic material that includes areas from which material
has been removed and attached material parts located in the areas
where material has been removed, the areas of the elastic material
in which material is removed having a lesser degree of resilience
than other areas of the elastic material in order to give different
areas of the elastic material different properties upon being
stretched.
5. An elastic material according to claim 4, wherein the areas from
which material has been removed include a pattern of
through-passing and/or blind holes.
6. A method according to claim 1, wherein said step of removing
material from said elastic material includes forming a pattern of
through holes in one portion of the elastic material and forming
pattern of blind holes in another portion of the elastic
material.
7. An elastic material according to claim 4, wherein the areas from
which material has been removed include a pattern of through holes
in one portion of the elastic material and a pattern of blind holes
in another portion of the elastic material.
8. A method according to claim 1, wherein material is removed from
the elastic material by passing the elastic material between a tool
cylinder which has a plurality of knife elements projecting
therefrom and a milling cylinder.
9. An elastic material according to claim 4, wherein said elastic
material includes areas from which no material has been removed.
Description
FIELD OF THE INVENTION
The present invention relates to a method of imparting varying
degrees of resilience or springiness to different areas of thin
elastic material, preferably the casing or enveloping material of
absorbent, disposable articles, such as disposable diapers and
incontinence guards. The invention also relates to a material
manufactured in accordance with this method, and an absorbent,
disposable article in which such a material is used as casing
material.
BACKGROUND OF THE INVENTION
It has become progressively more usual to provide disposable,
absorbent articles of the aforesaid kind with elastication with the
intention of improving the reliability of said articles against
leakage and also to adapt the shape of such articles to the body
shape of the wearer. This elastication often comprises elastic
threads or filaments attached to a casing layer of the article and
forming leg and waist elastic. It is also known to form waist
elastic from thermoplastic material having a so-called elastic
memory, instead of using elastic threads. The elastic properties of
such material are enhanced, by stretching said material to the
region of its plasticity range and thereby obtain a larger size.
When the material is subsequently heated, the material shrinks to
its original size and becomes elastic, so that it can be stretched
resiliently to its earlier stretched state. Such memory materials
afford technical advantages in manufacture in comparison with
elastic threads, since it is necessary to hold such threads
stretched during all the manufacturing stages of the article,
whereas the elasticity of the memory material is obtained by
heating the material after the article has been manufactured.
It is also known to use elastication for the purpose of imparting
to the absorbent pad of an absorbent disposable article of the
aforesaid kind a shape which will enable the article to be placed
in position on the wearer more readily and which will improve the
function of the article. Reference is made in this respect, for
instance, to Swedish Patent Specification No. 8406071-4, which
relates to such an article in which elastic threads are disposed in
the form of a network, such as to form a pattern having curved
parts, for instance curved leg elastic.
Furthermore, it is known from EP 0 098 983 to provide a diaper with
resilient casing material surrounding the absorbent pad or body,
such as to provide waist and leg elastic. In the case of this
diaper, the resilient material is not pre-stretched, which means
that it is necessary to produce all of the elastic force when
putting on the article. Consequently, when using casing material of
this kind it is not possible to deform the absorbent pad of a
diaper in order to improve diaper function.
Despite long-term efforts by diaper manufacturers to provide
improved shape-adaptability and improved leakage reliability with
the aid of elastication, no manufacturer has successfully produced
disposable, absorbent articles of the aforesaid kind which measure
up to the hitherto best solution in these respects, namely diapers
which are held on the child wearer with the aid of resilient pants
provided with waist and leg elastication and particularly
configured for the purpose intended.
OBJECTS AND SUMMARY OF THE INVENTION
The present invention relates primarily to a method by which
different areas on parts of a sheet of elastic material can be
readily given varying degrees of resilience such as to enable the
material to be adapted optimally to the functional requirements of
the casing material which embraces the absorbent body of a
disposable, absorbent article of the aforesaid kind. The inventive
method can, of course, also be applied in other instances where an
elastic material is required to exhibit varying degrees of
resilience in different areas thereof.
This object is achieved in accordance with the invention by
removing material from those parts or areas of the elastic material
which are to be given a lesser degree of resilience than remaining
areas or parts of said material, while leaving coherent material
parts in those areas from which material has been removed in order
to give different parts of the material different properties upon
stretching thereof. The method enables selective patterns or
removed material areas to be readily achieved. The method also
enables the casing material of disposable articles of the aforesaid
kind to be readily produced and with good precision with a desired
elastic pattern with varying degrees of resilience in different
areas of the pattern.
The invention also relates to material manufactured in accordance
with the method, and to a disposable, absorbent article whose
casing material comprises such resilient material.
In accordance with one preferred application of the inventive
method for the manufacture of disposable, absorbent articles of the
aforesaid kind, the elastic material consists of a so-called memory
material which is heated after the manufacture of the remainder of
the article has been completed.
BRIEF DESCRIPTION OF THE DRAWING FIGURES
An exemplifying embodiment of the invention will now be described
in more detail with reference to the accompanying drawings, in
which:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a diaper which includes casing material
manufactured in accordance with the inventive method; and
FIGS. 2-4 illustrate schematically an exemplifying embodiment of
apparatus for removing material from a material web.
BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 illustrates a diaper and shows the side of the diaper which
is intended to lie closest to the wearer in use. The diaper is
constructed in a conventional manner from an inner and an outer
casing material 1 and 2 respectively, and a T-shaped absorbent pad
3 located therebetween.
The inner casing material 1 includes a pattern of through-passing
and blind holes 4 and 5 respectively, which have been formed in the
casing material 1 in a manner and with the aid of means hereinafter
described. The through-passing holes 4 are disposed on that part of
the casing material 1 which extends over the absorbent pad 3,
whereas the blind holes 5 are disposed on those parts of the casing
material 1 which form side flaps externally of the absorbent pad.
The casing material 1 also includes imperforate parts 6, 7, 8, i.e.
parts from which no material has been removed.
The back and front ends of the outer casing material 2 include
imperforate parts 9 and 10 respectively from which no material has
been removed and which, in the FIG. 1 embodiment, are indicated by
mutually intersecting lines, and an intermediate part 11 in which
blind holes have been formed.
Attached, in a conventional manner, to the back end of the diaper
are two side-fastener tabs 12, 13 by means of which the sides of
the front and back parts of the diaper can be joined together, to
give the diaper a pants-like configuration.
The resilient materials forming the casing material of a disposable
diaper and provided with the aforedescribed pattern, in accordance
with the inventive method, preferably consist of mutually the same
or mutually different thermoplastic materials of the "memory type".
Subsequent to being heated, such material will contract to its
original size while remaining elastically stretchable from its
contracted state to an extended or stretched state. A suitable
material in this respect is, for instance, Exaflex, which is
marketed by the company Exxon.
The method of forming the through-passing and blind holes in the
casing materials 1 and 2 will now be described with reference to
FIGS. 2-4.
FIGS. 2-4 illustrate schematically a machine unit 14 which
functions to form holes in material and for thinning material in a
controlled fashion, i.e. a so-called perforating unit, which may be
a converted, commercially available machine unit originally
intended for perforating sheets of postage stamps or sheets of
labels.
The perforating unit 14 includes a tool cylinder 15 and a milling
cylinder 16 which coacts with the tool cylinder 15. A material web
A, which is to be perforated or in which holes are to be formed, is
passed between the two cylinders 15 and 16. The tool cylinder 15 is
provided with outwardly projecting knife-elements 17 which function
to remove material from the web A, as shown in FIG. 4. The
perforating unit also includes means (not shown) which enable the
distance between the rotational axes of the tool cylinder 15 and
the milling cylinder 16 to be accurately adjusted, so that in the
working position the knife-elements 17 can be located at a distance
from the peripheral surface of the milling cylinder and therewith
thin the material web A solely by removing material therefrom.
When the knife-elements 17 occupy the position illustrated in FIG.
4, the knives will form through-passing holes in the web A. It will
be understood that the tool cylinder can be provided with
knife-elements of mutually different height, so as to produce
through-passing holes and blind holes at the same time.
The perforating unit 14 also includes grinding equipment 18 for
sharpening the knife-elements 17, means for advancing the web A
through the unit. 14, and means for driving the tool cylinder and
milling cylinder respectively.
In the case of the illustrated preferred embodiment, the
knife-elements 17 are configured to produce circular
through-passing and blind holes in the pattern illustrated in FIG.
1. The knife-elements may, of course, be given another
configuration, for instance a rectangular configuration. If it is
desired to produce coherent areas from which of web material has
been removed larger than those that can be produced by means of a
single pair of tool and milling cylinders, the perforating unit can
be provided with several such pairs and said pairs arranged to
produce mutually overlapping patterns of removed web-parts.
Thus, desired patterns of areas in which material is removed can be
achieved by appropriate design of the perforating unit.
When the resilient material is not a memory material, but a
conventional resilient material and the perforating unit or units
is, or are, installed in the diaper manufacturing line, the
perforating units may conveniently be provided with means which
enable the resilient material to be fed through a respective
perforating unit in a pre-tensioned, i.e. stretched, state.
In accordance with one advantageous variant of the invention, the
inner casing material 1, and therewith the aforedescribed material
web A, may consist of a two-ply material comprising a laminate of
resilient material and non-woven material.
In the manufacture of the diaper illustrated in FIG. 1, the casing
materials are advantageously fed through a conventional diaper
manufacturing line in a stretched state, i.e. prior to the final
heating stage in which said materials strive to return to their
original dimensions. The final heating of the respective casing
materials is thus effected subsequent to having joined together
those parts of the inner and outer casing materials which lie
externally of the absorbent pad, said material parts preferably
being glued together.
This avoids the complication that constantly manifests in
manufacture when using conventional casing materials which
incorporate elastic elements, namely that these elements, for
instance elastic threads, must be held stretched during the
manufacture of said diapers.
The diaper illustrated in FIG. 1 has not yet been subjected to said
final heating stage. Thus, when the diaper illustrated in FIG. 1 is
heated, the casing materials 1 and 2 will strive to return to their
original size. However, this reduction in size of the casing
materials is counteracted by the relatively rigid absorbent pad 3,
this counteraction being of a greater or lesser degree due to
varying degrees of elasticity in different parts of the casing
materials. In the illustrated embodiment, the elastic force in the
parts 7 and 8 of the inner casing material are sufficiently great
to deform the absorbent body and therewith generate a basin-like
shape within the region of the part 7 and a gutter-like shape in
the region of the part 8. The elastic forces in the parts 9 and 10
of the outer casing material are sufficiently great to compress the
absorbent pad slightly in its transverse direction. The elastic
forces in remaining parts lying inwardly of the absorbent body are
too small for the casing materials to be able to shrink in size
against the influence exerted by the rigidity of the absorbent pad.
However, the endeavors of the memory material to return to its
original size ensures that no folds are formed in the casing
materials in conjunction with the deformation of the absorbent pad
caused by the material parts 7-10.
The absorbent pad also influences the reduction in size of external
casing parts located nearest said pad, these parts being joined
together in a conventional fashion, by preventing contraction of
said parts, particularly in their longitudinal direction. The outer
casing parts, however, are able to contract without hinder from the
absorbent pad.
Thus, it is possible by means of the present invention to produce
an all-in-one diaper incorporating waist and leg elastic of the
same quality as the elastic pants normally used to hold diapers
against the body of the wearer, and comprising casing material
which resiliently urges the absorbent pad against the body of said
wearer. Furthermore, the configuration of the casing material of
the diaper illustrated in FIG. 1 will also cause the absorbent pad
to adopt a basin-like shape in the region of the wetting point and
a gutter-like shape in the crotch region of the diaper when worn,
these configurations being beneficial with respect to the
absorption capacity and leakage reliability of the diaper.
The described, exemplifying embodiment should be seen solely as a
non-restrictive example of how a resilient material can be
configured in accordance with the invention. It will be understood
that many variants are conceivable to one skilled in this art,
particularly with respect to the selected pattern and material
combinations. This also applies to the illustrated application of
the inventive casing material. For instance, the outer casing
material may be provided with conventional waist elastic and solely
the inner casing material may comprise an inventive resilient
material. The scope of the invention is therefore restricted solely
by the scope of the following Claims.
* * * * *